[analyzer][NFC] Make sure that the BugReport is not modified during the construction of non-visitor pieces

I feel this is kinda important, because in a followup patch I'm adding different
kinds of interestingness, and propagating the correct kind in BugReporter.cpp is
just one less thing to worry about.

Differential Revision: https://reviews.llvm.org/D65578

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@368755 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/StaticAnalyzer/Core/BugReporter/BugReporter.h

@@ -105,6 +105,7 @@ protected:
 
   const ExplodedNode *ErrorNode = nullptr;
   SmallVector<SourceRange, 4> Ranges;
+  const SourceRange ErrorNodeRange;
   ExtraTextList ExtraText;
   NoteList Notes;
 
@@ -155,16 +156,22 @@ protected:
   llvm::SmallSet<const ExplodedNode *, 4> TrackedConditions;
 
 public:
-  BugReport(const BugType& bt, StringRef desc, const ExplodedNode *errornode)
-      : BT(bt), Description(desc), ErrorNode(errornode) {}
+  BugReport(const BugType &bt, StringRef desc, const ExplodedNode *errornode)
+      : BT(bt), Description(desc), ErrorNode(errornode),
+        ErrorNodeRange(getStmt() ? getStmt()->getSourceRange()
+                                 : SourceRange()) {}
 
-  BugReport(const BugType& bt, StringRef shortDesc, StringRef desc,
+  BugReport(const BugType &bt, StringRef shortDesc, StringRef desc,
             const ExplodedNode *errornode)
       : BT(bt), ShortDescription(shortDesc), Description(desc),
-        ErrorNode(errornode) {}
+        ErrorNode(errornode),
+        ErrorNodeRange(getStmt() ? getStmt()->getSourceRange()
+                                 : SourceRange()) {}
 
   BugReport(const BugType &bt, StringRef desc, PathDiagnosticLocation l)
-      : BT(bt), Description(desc), Location(l) {}
+      : BT(bt), Description(desc), Location(l),
+        ErrorNodeRange(getStmt() ? getStmt()->getSourceRange()
+                                 : SourceRange()) {}
 
   /// Create a BugReport with a custom uniqueing location.
   ///
@@ -323,7 +330,7 @@ public:
   }
 
   /// Get the SourceRanges associated with the report.
-  virtual llvm::iterator_range<ranges_iterator> getRanges();
+  virtual llvm::iterator_range<ranges_iterator> getRanges() const;
 
   /// Add custom or predefined bug report visitors to this report.
   ///

include/clang/StaticAnalyzer/Core/BugReporter/BugReporterVisitors.h

@@ -82,7 +82,7 @@ public:
   /// Generates the default final diagnostic piece.
   static PathDiagnosticPieceRef getDefaultEndPath(const BugReporterContext &BRC,
                                                   const ExplodedNode *N,
-                                                  BugReport &BR);
+                                                  const BugReport &BR);
 };
 
 /// Finds last store into the given region,

lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountDiagnostics.h

@@ -67,7 +67,7 @@ public:
               ExplodedNode *n, SymbolRef sym,
               StringRef endText);
 
-  llvm::iterator_range<ranges_iterator> getRanges() override {
+  llvm::iterator_range<ranges_iterator> getRanges() const override {
     if (!isLeak)
       return BugReport::getRanges();
     return llvm::make_range(ranges_iterator(), ranges_iterator());

lib/StaticAnalyzer/Core/BugReporter.cpp

@@ -192,13 +192,17 @@ public:
 };
 
 /// Contains every contextual information needed for constructing a
-/// PathDiagnostic object for a given bug report. This class (and aside from
-/// some caching BugReport does in the background) and its fields are immutable,
-/// and passes a BugReportConstruct object around during the construction.
+/// PathDiagnostic object for a given bug report. This class and its fields are
+/// immutable, and passes a BugReportConstruct object around during the
+/// construction.
 class PathDiagnosticBuilder : public BugReporterContext {
   /// A linear path from the error node to the root.
   std::unique_ptr<const ExplodedGraph> BugPath;
-  BugReport *R;
+  /// The bug report we're describing. Visitors create their diagnostics with
+  /// them being the last entities being able to modify it (for example,
+  /// changing interestingness here would cause inconsistencies as to how this
+  /// file and visitors construct diagnostics), hence its const.
+  const BugReport *R;
   /// The leaf of the bug path. This isn't the same as the bug reports error
   /// node, which refers to the *original* graph, not the bug path.
   const ExplodedNode *const ErrorNode;
@@ -257,7 +261,7 @@ private:
   ExecutionContinues(llvm::raw_string_ostream &os,
                      const PathDiagnosticConstruct &C) const;
 
-  BugReport *getBugReport() const { return R; }
+  const BugReport *getBugReport() const { return R; }
 };
 
 } // namespace
@@ -2172,14 +2176,13 @@ const Stmt *BugReport::getStmt() const {
   return S;
 }
 
-llvm::iterator_range<BugReport::ranges_iterator> BugReport::getRanges() {
+llvm::iterator_range<BugReport::ranges_iterator> BugReport::getRanges() const {
   // If no custom ranges, add the range of the statement corresponding to
   // the error node.
   if (Ranges.empty()) {
     if (const auto *E = dyn_cast_or_null<Expr>(getStmt()))
-      addRange(E->getSourceRange());
-    else
-      return llvm::make_range(ranges_iterator(), ranges_iterator());
+      return llvm::make_range(&ErrorNodeRange, &ErrorNodeRange + 1);
+    return llvm::make_range(ranges_iterator(), ranges_iterator());
   }
 
   // User-specified absence of range info.

lib/StaticAnalyzer/Core/BugReporterVisitors.cpp

@@ -267,7 +267,7 @@ void BugReporterVisitor::finalizeVisitor(BugReporterContext &,
 PathDiagnosticPieceRef
 BugReporterVisitor::getDefaultEndPath(const BugReporterContext &BRC,
                                       const ExplodedNode *EndPathNode,
-                                      BugReport &BR) {
+                                      const BugReport &BR) {
   PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(
       EndPathNode, BRC.getSourceManager());